DOA Estimation of Coherent Signals Based on Direct Data Domain Under Unknown Mutual Coupling

Performance of high-resolution direction-of-arrival (DOA) estimation based on the orthogonality of subspaces is degraded by array manifold perturbation and rank loss of covariance matrix resulted from mutual coupling (MC) and multipath propagation, respectively. In this letter, an MC auto-suppression DOA estimation method based on direct data domain (D3) is proposed for coherent signals impinging on a uniform linear array (ULA). An equivalent covariance matrix is directly constructed with part of the array output, and it is used to carry out both decoherence of signals and MC suppression of array simultaneously. Because calculation of a covariance matrix of sample is not needed, the method has a low computational burden and high real-time performance. Without any array calibration, the method achieves a favorable robustness and accuracy of DOA estimation under unknown MC. The simulation results demonstrate the validity of the proposed method.